Support preconfigured args in stdinservice.

PiperOrigin-RevId: 802948632

Author: Copybara Service

fleetspeak/src/client/stdinservice/proto/fleetspeak_stdinservice/config.pb.go

@@ -8,4 +8,8 @@ option go_package = "github.com/google/fleetspeak/fleetspeak/src/client/stdinser
 // in ClientServiceConfig.config.
 message Config {
   string cmd = 1;
+
+  // Command line arguments.
+  // These arguments are prepended to the arguments specified in the message.
+  repeated string args = 2;
 }

fleetspeak/src/client/stdinservice/proto/fleetspeak_stdinservice/config.proto

@@ -11,6 +11,7 @@ message InputMessage {
   bytes input = 1;
 
   // Command line arguments.
+  // These arguments are appended to the arguments specified in the config.
   repeated string args = 2;
 }
 

fleetspeak/src/client/stdinservice/proto/fleetspeak_stdinservice/messages.pb.go

@@ -81,7 +81,11 @@ func (s *StdinService) ProcessMessage(ctx context.Context, m *fspb.Message) erro
 
 	var stdout, stderr bytes.Buffer
 
-	cmd := exec.CommandContext(ctx, s.ssConf.Cmd, im.Args...)
+	var args []string
+	args = append(args, s.ssConf.Args...)
+	args = append(args, im.Args...)
+
+	cmd := exec.CommandContext(ctx, s.ssConf.Cmd, args...)
 	cmd.Stdin = bytes.NewBuffer(im.Input)
 	cmd.Stdout = &stdout
 	cmd.Stderr = &stderr

fleetspeak/src/client/stdinservice/proto/fleetspeak_stdinservice/messages.proto

@@ -32,7 +32,8 @@ func TestStdinServiceWithEcho(t *testing.T) {
 	s, err := Factory(&fspb.ClientServiceConfig{
 		Name: "EchoService",
 		Config: anypbtest.New(t, &sspb.Config{
-			Cmd: "python",
+			Cmd:  "python",
+			Args: []string{"-c", `import sys; sys.stdout.write(" ".join(sys.argv[1:]))`},
 		}),
 	})
 	if err != nil {
@@ -51,7 +52,7 @@ func TestStdinServiceWithEcho(t *testing.T) {
 		&fspb.Message{
 			MessageType: "StdinServiceInputMessage",
 			Data: anypbtest.New(t, &sspb.InputMessage{
-				Args: []string{"-c", `import sys; sys.stdout.write("foo bar")`},
+				Args: []string{"a", "b"},
 			}),
 		})
 	if err != nil {
@@ -70,7 +71,7 @@ func TestStdinServiceWithEcho(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	wantStdout := []byte("foo bar")
+	wantStdout := []byte("a b")
 	if !bytes.Equal(om.Stdout, wantStdout) {
 		t.Fatalf("unexpected output; got %q, want %q", om.Stdout, wantStdout)
 	}